Dictionary.com refers to the word quit this way:
–verb
1. to stop, cease, or discontinue: She quit what she was doing to help paint the house.
2. to depart from; leave (a place or person): They quit the city for the seashore every summer.
3. to give up or resign; let go; relinquish: He quit his claim to the throne. She quit her job.
4. to release one’s hold of (something grasped).
5. to acquit or conduct (oneself).
6. to free or rid (oneself): to quit oneself of doubts.
7. to clear (a debt); repay.
The interesting connection to all of the forms of the definition is that quitting is a personal thing. “He” quit, “She” quit, “They” quit. This infers an ability to make a choice. Drug rehab always starts with a personal choice. No one can heal someone if they refuse to seek assistance, after all, and even the most exclusive drug rehab centers are powerless to help a client who refuses to walk through the front door.
Drug rehabilitation is sometimes part of the criminal justice system. People convicted of minor drug offenses may be sentenced to rehabilitation instead of prison, and those convicted of driving while intoxicated are sometimes required to attend Alcoholics Anonymous meetings.
With or without the inclusion of the criminal court system the success of any drug quitting program has to do with the complete personal conviction of a person to want to quit. That desire is what makes the difference. In the end, no one can force any one person, court ordered or not, to quit.